Airplane and control device therefor



June 15, 1943. F. R. MAXWELL y 2,321,837

I AIRPLANE`AND CONTROL DEVICE'THEREFOR- Filed Nov. v12, 1940 5shets-sheet 1v M\ www.

June 15, 1943. F. R. MAXWELL AIRPLANEfAND CONTROL DEVICE THEREFQR IFiled Nov.v 12, 1940 5 Sheets-Sheet 2 `lune 15, 1943. F. R. MAXWELLAIRPLANE AND CONTROL DEVICE THEREFOR Filed Nov. l2, 1940 5 Sheets-Sheet3 June 15, 1943. F. R. MAXWELL AIRPLANE AND CONTROL DEVICE THEREFORFiled NOV. l2, 1940 v 5 Sheets-Sheet 4v Patented June l5, 1943 istarmene irrank Et. liaxweil, ester, Pa.

- asentar I ain-,i7

A'reNl'r' j ci' aan contraer. navos EBEE Appiication November l2; i946,Serial No. 3651,34?

6 Unitime. (@a Zmm) the nose of the wing until the pilot moves the flap.

Numerous control devices have heretofore been incorporated in airplanewings to permit a high speed in flight and at the same time enable lowvide a novel nose slotfor an airplane wing in which the upper and loweropenings of the slot are closed by covers and in which vthe lower covercan open sulciently to aord a smooth contour in the slot when the upper-cover is partially opened and to thereafter remain in such posi tion sothat the contour of the'slot will remain smooth as the upper cover isopened further.

speed takeoil's and permit the airplane to land lin relatively smallareas. Of course the idea of interconnecting a nose slot and a trailingedgeilap is not novel, but to my knowledge an inter- I connected slotandflap combination in whichv the slot is positively locked againstopeningmovement until the ilap has begun to move has never beenproposed. 'I'he disadvantages of having the nose slot open duringcertain stages of flight is believed readily apparent and anyconstruction which will obviate such a. step taking place is a.

opening movement due to aerodynamic forces acting on the wing until theap begins to move.' Yet a further object of this invention is to providea wingihaving an interconnected slot and iiap in which the connectinglinkage is so ar- -ranged thatit exerts its greatest mechanical forcewhen the greatest aerodynamic-forces are acting on the slot or ap.

limi another object is to provide an airplane wing having a. slot whichextends through the y wing adjacent to the leading edge thereof withcovers for the upper` and lower openings of said slot, said covers intheir closed -position conforming to the upper and lower contours ofythe wing and means to move the lower cover into contact with the uppercover to give an airfoil section to the upper cover upon initialmovement of the upper cover andto maintain this airfoil section duringall further movement of the upper cover.

thereby affording optimum airow through the slot.

Yet another object of this invention is Itoprcthe upp'er and loweropenings of the slot are.

closed by cover members, the upper cover member being pivoted to thenose of the wing and the lower cover member being hinged tothe uppercover member.

Another object ofthe present invention is to provide al slot and'iiapcombination for a wing in which the connecting linkage between the slotand ila-p is provided with a locking device 'either adjacent-I to theslot, adjacent to the flap, or intermediate the slot and'ilap toprevent' the aerodynamic forces actingv on the nose ofthe wing fromopening the slot until the nap' begins to move. 1

- 'And an additional object vof the present inven* this invention`comprises providing a slot adjacent to the leading edge of the wing anda fiap near the trailing edge of the wing. The upper and lower openingsof the slot are adapted to be closed by covers which conform 'to thecontour of the upper and lower vsurfaces of the wing in' their closedposition; Linkage connects the flap to the upper'coverand there is aconnection to the lower cover which is operated by movement of thelinkage. A control extends from the operating linkage to thecockpit orthe fuselage of the airplane sothat the pilot may actuate the slot andiiap by a single control.

The linkage is of such nature that the flap may move through a smallangle before the slot opens and the aerodynamicv forces working on theleading edge of the wing cannot open the upper cover until the pilot hasmoved the nap. Furthermore, the connection vto the lower cover willpermit the lower cover to move intol contact with the upper cover togive an airfoil section to the upper cover upon the initial move- 'mentof the upper cover. and will maintain this and flap combination showingthese parts in the closed position.

Figure 2 is a fragmental transverse sectional view of the layout shownin Figure 1 illustrating the different opening movement of the slot andflap, the slot and flap being shown in the closed position in the fulllines.

Figure 3 is a fragmental transverse sectional view of the nose of a wingshowing the lower slot cover pivoted tothe upper cover, the slot beingin the closed position.

Figure 4 is a transverse sectional view of .an airplane wing equippedwith another form of my invention.

Figure 5 is a fragmental transverse sectional view of the structureshown in Figure 4 showing the different opening movements of my slot andflap combination.

Figure 6 is a transverse sectional view oi' a still further form of mynovel nose slot and flap combination.

Figure 7 is a fragmental transverse sectional view of the constructionshown in Figure 6 illustrating the different movements of the slot andap.

Figure 8 is a transverse sectional view of an airplane wing showing astill further form of my invention. f

Figure 9 is a sectional view taken along the line 9-'9 of Figure 8looking in the direction of the arrows.

Figure 10 is a side elevational view of the operating unit for movingthe slot and flap shown in Figure 8.

Figure l1 is a diagrammatic representation of the connecting linkageshown in Figure 1.

Figure 12 is a diagrammatic representation of the connecting linkageshown in Figure 4.

Figure 13- is a diagrammatic representation of the connecting linkageshown in Figure 6.

Referring to Figures l and 2 I have shown an airplane wing I of anysuitable construction having internal spars 2, a slot 3 which extendsthrough the wing adjacent to the leading edge thereof and a flap 4provided near the, trailing edge of the wing. 'I'he wing I is formedwith a recess or well 5 in which the flap 4 is pivoted as shown at 6. Anarm l is hinged to the flap and an operating rod 3 is pivoted to thefree end of the arm 1 as indicated at 3. The rod 3 is suitably connectedto the flap operating mechanism (not illustrated) located within thecockpit or fuselage of the airplane.

There is also attached to theap 4 a short arm II) to which is pivoted atII a long operating link or push rod I2. As clearly shown in Figure 1,the operating rod I2 extends to a point adjacent to the slot 3 and ispivoted at I3 to one arm of a bell crank I4 which is pivoted `at I5 tothe internal structure of the wing.

The upper opening of the slot 3 is adapted to be closed by a cover I6which is hinged to the nose of the wing I, as shownat I1. A second slotcover I8 for the lower opening of the slot isalso hinged at the pointI1. As clearly shown in the drawings, when the covers I6 and I8 are intheir closed positions, they conform to the contour of the upper andlower surfaces of the wing I, thereby affording an airfoil section.

A push rod Il is pivoted to the other arm of the bell crank I4, vasshown at 23. I'he free end of the rod I3 is pivoted to the undersurfaceof the cover I5, as shown at 2|. A toggle link 22 is hinged to the lowercover Il, as shown at 22', and an elongated lever 23 is pivoted to thelink 22. The lever 23 is pivoted to the cover I5, as shown at 24, and isformed with a short oiset portion 25. A rod 25 is pivoted to the offsetportion 25, as shown at 21, and the rod 25 is further formed with a lostmotion slot 28 in which is adapted to move a pin 28 carried by the bellcrank I4. The rod 25 is attached to one of the internal spars by atension spring 33.

It is thought apparent that since the pivot points 5, II and I5 are inline when the slot 3 and flap 4 are in their closed positions, it is notpossible for the aerodynamic forces working i I on the leading edge ofthe wing to rock the bell crank I4 about its pivot I5 to cause the upperslot cover I5 to open. This is a very important feature o! the presentinvention in that it will positively prevent the slot in the leadingedge of the wing from being opened except when such opening is desiredby the pilot of the airplane.

When the pilot operates his control to lower the .i'lap it will beappreciated that the flap 4 may move through an angle of approximately15 vbefore the bell crank I4 begins to rock about its pivot I5 to openthe cover I6. This is very desirable in that there are certain flightconditions where it is desired to have some flap movements withoutopening the slot. When the bell crank has rocked suillciently to causethe push rod I3 to open the cover I8 slightly, the oiIset portion 25 andthe link 23 will move thelower slot cover I3 into a well or recess 3lprovided in the upper slot-cover I5, as showninFigure 2. This will givean airfoil section to the upper cover I5 and as the upper slot cover ismoved further, the lower slot cover will remain in its nested positionand thus afford optimum airflow through the slot 3. f

Referring to Figure 3, I have shown a somewhat modified form of leadingedge slot. The connections between the slot 3 and the flap 4 and theoperating mechanism for opening and closing the slot are the same as thestructural details illustrated in Figures 1 and 2. However, it will benoted that a hinge pin 40 which extends through the leading edge of thewing I supports a closure membery 4I for the upper opening of 4the slot3. The upper closure 4I is of stressed skin construction and may includea load carrying strength member, such as, a box beam 4I', as clearlyshown in Figure 3. Obviously, other types of strength members may beused. A lower closure 42 for the slot is hinged to the box beam 4I', asshown at 43. (The lower cover may also be of stressed skinconstruction.) This slot operates in the same manner as the one shown inFigures 1 and 2.

In Figures 4 and 5, there is covered a still further form of myinvention. In this modification, the operating link I2 is hinged at 5lto one arm of a bell crank 5I and the bell crank is pivoted at 52 to theinternal structure of the wing I. A second operating link 53 is pivotedto the other arm of the bell crank, as shown at 54. The opposite end ofthe link 53 is pivoted at I3 to the bell [crank I4 which operates theupper slot cover I5.

It should be noted (Figure 4) that when the slot 3and the flap 4` are inthe closed positions line, thereby aording a lock, and it is notpossible for the aerodynamic forces acting on the nose of the wing I toopen the upper slot cover I6'. Clearly, the slot 3 can only be openedwhen the pilot manipulates his controls to lower the ilap 4 to rock thebell crank 5l about the pivot 52.

be moved about the pivot I5, enabling the slot s to be opened. In viewof the fact that the points Illll, 98 and IIIZ are in a. straight line,it is not possible for the aerodynamical forces working on In Figures 6and 7, there is shown anotherv form of slot and flap combination inwhich the mechanism holding-the upper slot cover I6 in its closedposition is adjacent to the slot 3. In this form, it can be seen thatthe operating link I2 is pivoted at I3 to a lever 68 which is pivoted at9i to the internal structure of the wing I at .a point adjacent to thenose. A push rod 62 is pivoted to the lever 88 as shown at 63, and. tothe upper slot cover as shown at 66. The rod 62 is Y curved' asindicated at* 65 so that it will not interfere with the pivot point 6Iof the lever S8.

Pivoted to the lower slot cover I8 as shown at 6@ is a short rod 61.4Secured to the end of the roel 6l is a sleeve 68 in which is disposeda-helical spring 69. Pivoted at 'lIlto the lever 6a is a rod ll whichextends into the sleeve 99. A pin 'I2 provided on the rod ilprojectsthrough a lost motion slot I3 provided in the sleeve 63. It isthought obvious therefore that when the lever 99 is moved about itspivot 6I by the lowering of the flap Il, the rod 'II will slide inthesleeve 8B,v

compressing the spring 69, thereby'causing the lower slot cover I8 tomove to the broken line position shown in Figure 7 whereby a smoothcontour is provided in the slot 3.

It should be further observed that the pivot' points I3, SI and 63 arein a substantially straightA .slot 3 is adjacent to the pilot of theairplane.

In Figure 9, it will be noted that the ap horn 'I is pivoted at 88 tothe push rod 8. The push rod 9 in turn is pivoted at 8| to a link 82hinged at 83 to a supporting member 84 of the wing I. A second link 85is also pivoted at 8l to the rod 8 and at 8l to a nut 88. The nut 88engages screw threads 89 provided on a shaft 90 journaled at 9i in theinternal structure of-the wing` I. A sprocket 92 is provided for theshaft and a, chain 93 is trained over the sprocket I92. The chain alsoruns over a second sprocket 913 provided on a shaf t 95 which isrotatably mounted in the cockpit or fuselage of the plane. The shaft 95has formed therein a worm 96 which meshes with a segment 91 `alsosupported in the cockpit as shown at 98. :An operating handle 99 isprovided for imparting movement to the shaft 95.

Attached to the segment 971, as indicated at IMI, is a rod lill which ispivoted to arms I82 carried by a shaft AIIl3 journaled in the internalstructure of the wing. Also attached to the shaft I83 are arms Ill4'towhich is pivoted at |85 the operating link I2.

It is thought apparent that when the pilot rotates the shaft 95 by thehandle 99, the shaft 9Illwill .be rotated and the -ap II will be loweredf byvirtue of the movement of the nut 8l along the screw Vthreads 89. Atthe same time the arm |04 will be moved rearwardly, thus pulling the thewing to open the upper slot cover I6.

In Figures 11 to`13, I have shown diagrammatically` the linkage thatinterconnects the slot and iiap which tend to normallybalance each otheraerodynamically.

It will be noted that when the iiap approaches its position. normal tothe airstream, the air forces affecting the flap movement decreasetoward zero. Simultaneously, the slot is closing and the air forcestending to open the slot cover increase. Duringthis movement, the toggleeffect of the linkage is also increasing which` compensates for theincreased air force on the slot cover.

From the foregoing description, it will bey appreciated that I haveprovided a wing having an interconnected slot and ap in which theconnecting linkage is so arranged that it exerts its greatest mechanicalforce when' the greatest aerodynamic forces are acting on the slot ornap. More specifically, as the flap and slot move, the toggle eect ofthe linkage tends to balance the aerodynamic forces acting on them.Moreover, the slot is provided with upper and lowercovers 'having meansto move the lower cover into contact with the upper cover to give anairfoil section to the upper 'cover upon initial movement of the uppercover and to maintain this airfoil section during .all further movementof the upper cover. In addition, the upper cover under certaincircumstances may be pivoted to the nose of the wing and the lower covermay be hinged to the upper cover. The linkage connecting the slot l andflap may be provided with a locking device link I2 rearwardly, causingthe bell crank Il to 75 4either near the slot, adjacent to the ap, or.

intermediate the slot and flap to prevent the aerodynamic forces actingon the wing from opening the slot until the flap begins to move.

While I have shown and described the preferred embodiment of myinvention, I wish it to be understood that I do notl confine myself tothe precise details of construction herein set forth by way vofillustration, as it is apparent that many changes and variations may bemade therein, by

those skilled. in the art, without departing from` the spirit of theinvention, or exceeding the scope of the appended claims.

I claim: 1. An airfoil comprising a. main section having a slot adjacentits leading edge extending transversely to the line of flight, an uppercover for the slot formed as a unitary l strength member and including alongitudinal spar providing a leading edge for the main sectionthroughout the extension of the slot,.and a pivot affording a connectionedge for the main section throughout the extension of the slot, a pivotaffording a connection between said spar and the main section, a lowercover for the slot and members forming operative connections betweensaid covers whereby they.

may be rendered cooperatively operative.

3. An airfoil according to claim 2,characterized by the fact that thelower cover is pivotauy supported from the upper cover.

4. An airfoil comprising a main section having a slot adjacent itsleading edge extending transversely to the line of flight, an uppercover for the slot formed as a unitary strength member and including alongitudinal spar providing a leading edge for the main sectionthroughout the extension of the slot and ribs supported by the spar andextending transversely of the upper slot and including aiongitudinalspar providing a leading edge for the Amainsectionthroughout the extension o! the slot, a pivot aording aconnection between said spar and the main section, said cover in itsextension rearwardly being of varying thickness and a support connectedto said cover at a point to the rear of its point of greates thickness.

6. An airfoil comprising a. main section having a slot adjacent itsleading edge extending transversely to the line of ilight, an uppercover for the slot formed as a unitary strength member and including a.longitudinal spar providing a leading edge for the main sectionthroughout the extension of the slot and ribs supported by the spar and.extending transversely of the upper slot cover, a pivot affording aconnection between said spar and the main section, said cover in itsextension rearwardly being of varying thickness and a support connectedto said cover at a point to the rear of its point of greatest thickness.

FRANK R. MAXWELL.

